The main principle of the 3D display technology lies in that the right eye and the left eye of a viewer receive different images, respectively, and the image received by the left eye and the image received by the right eye are analyzed and overlapped by the viewer's brain so that the viewer may sense hierarchy of the images, thus obtaining a stereoscopic sense.
Currently, 3D displays mainly include two kinds: one kind requires wearing 3D glasses, and the other kind is a naked-eye 3D display. Parallax barrier technology belongs to the naked-eye 3D technology. However, the existing 3D display based on the parallax barrier technology can be viewed only in the horizontal screen condition or in the vertical screen condition, which make the viewer see the 3D effect only in one condition.